Knuckle rings, also known as knuckledusters and brass knuckles, are traditionally four linked rings that fit through the fingers providing a strong metal surface across the knuckles. This allows you to hit harder in a fight or battle. One of the earliest known forms of knuckle rings came from ancient Rome; the cestus was a battle glove in which leather straps were sewn across the knuckles increasing the hardness of the knuckle and therefore the power of the punch.

Knuckle rings are either worn for practical use or as a fashion statement. Either way, the concept is the same: there are between two to four over-sized loops that fit in-between the fingers and rest at the knuckles. The stretch of metal or plastic across the knuckles may be studded, spiked or incorporate a decorative design. For practical fighting usage, spikes and studs cause extra harm to the opponent when punching with the fists. Knuckle rings worn for fashion may be studded with plastic spikes or fake jewels.

While one of the earliest known forms of knuckle rings was the cestus, which is depicted in the ancient sculpture The Boxer of Quirinal in Rome, knuckle rings have been made and used for centuries around the world. For example, the tekko is a form of knuckle ring inspired by a horse shoe in Okinawa. The tekko is used mostly in martial arts. In the first and second World Wars, American soldiers were given trench knives in which the handle was fashioned into knuckle rings.

In the United States, legitimate knuckle rings are considered an illegal weapon in some states while other states require you to have a permit for concealed weapons. For example, in states such as California, Illinois and Vermont, knuckle rings are illegal, however, in South Carolina brass knuckles are illegal only if used with the intent to hurt someone. Before you consider purchasing legitimate knuckle rings, meaning knuckle rings made of metal, check your state's law on possession.

In modern times knuckle rings are still used for fighting but are also commonly worn as a fashion statement. Knuckle rings worn for fashion may be made of metal or plastic, considering they are not used for fighting, and may be studded with fake jewels. Often these rings will sport a glitzy design or symbols such as initials or dollar signs. The fashion statement typically glorifies violence and wealth but can also be artistic, creative and bizarre.